RFR 8039080: "jinfo server_id at host" fails with "Invalid process identifier"

[Jaroslav Bachorik]

Please, review the following fix in "jinfo" launcher.

Issue : https://bugs.openjdk.java.net/browse/JDK-8039080
Webrev: http://cr.openjdk.java.net/~jbachorik/8039080/webrev.00

When switching "jinfo" to utilize diagnostic commands when possible a 
combination of launcher arguments was omitted causing "jinfo" fail to 
execute the default action (-flags & -sysproperties) against a remote SA 
debug server.

The patch fixes this omission. Additionally it contains a refactoring to 
make the launcher argument parsing testable via a unit test (testng). 
Also, a new test is provided covering the possible argument combinations.

Thanks,

-JB-